To detect the position of a vehicle occupant, it is known to use a passenger-compartment sensory system. There are intelligent and passive passenger-compartment sensory concepts which are conceived as sensor systems. These include ultrasonic sensors, active infrared sensors, passenger-compartment cameras, in particular stereo-video or stereo-CCD cameras, radar sensors, and, in this context, in particular SAR radar concepts (synthetic aperture radar), absolute-weight sensors, for example those based on wire strain gauges, occupant-classification sensors, for example seat-mat, seat-position, headrest-position, seat-back-inclination, seat-belt-usage, seat-belt-load, child-seat-occupancy detection sensors or also combinations of such sensor concepts. This information is then used for triggering occupant-restraint systems.
German Published Patent Application No. 198 56 311 describes the output of an acoustic and/or and optical warning as a function of the sitting position of a vehicle occupant. In this context, the out-of-position position is monitored in particular. In German Published Patent Application No. 199 00 395, besides outputting a warning in response to an out-of-position position, the airbag is also disabled.